package com.sgq.vue.utils.system;

import com.sgq.vue.entity.system.User;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

@Data
@ConfigurationProperties(prefix = "jwt")
@Component
public class JwtUtils {
    //密钥
    private String secret;
    //过期时间毫秒
    private Long expiration;
    //请求头名字
    private String tokenHeader;
    //token前缀
    private String tokenHead;


    public Long getExpiration() {
        //以秒作为时间 15 * 60
        return expiration * 60;
    }

    /**
     * 从数据声明生成令牌
     *
     * @param claims 数据声明
     * @return 令牌
     */


    private String generateToken(Map<String, Object> claims) {
        Date expirationDate = new Date(System.currentTimeMillis()+ expiration * 1000 * 60 );
        return Jwts.builder()
                .setClaims(claims)
                .setExpiration(expirationDate)
                .setIssuedAt(new Date())
                .signWith(SignatureAlgorithm.HS512, secret)
                .compact();
    }


    /**
     * 生成令牌
     *
     * @param userDetails 用户
     * @return 令牌
     */
    public String generateToken(UserDetails userDetails) {
        Map<String, Object> claims = new HashMap<>(2);
        claims.put(Claims.SUBJECT, userDetails.getUsername());
        claims.put(Claims.ISSUED_AT, new Date());
        return this.tokenHead + generateToken(claims);
    }

    /**
     * 从令牌中获取数据声明
     *
     * @param token 令牌
     * @return 数据声明
     */
    public Claims getClaimsFromToken(String token) {
        Claims claims;
        token = token.replace(this.tokenHead,"");
        try {
            claims = Jwts.parser()
                    .setSigningKey(secret)
                    .parseClaimsJws(token)
                    .getBody();
        } catch (Exception e) {
            claims = null;
        }
        return claims;
    }


    /**
     * 从令牌中获取用户名
     *
     * @param token 令牌
     * @return 用户名
     */
    public String getUsernameFromToken(String token) {
        String username;
        try {
            Claims claims = getClaimsFromToken(token);
            username = claims.getSubject();
        } catch (Exception e) {
            username = null;
        }
        return username;
    }

    /**
     * 判断令牌是否过期
     *
     * @param token 令牌
     * @return 是否过期
     */
    public Boolean isTokenExpired(String token) {
        Claims claims = getClaimsFromToken(token);
        Date expiration = claims.getExpiration();
        return expiration.before(new Date());
    }

    /**
     * 刷新令牌
     *
     * @param token 原令牌
     * @return 新令牌
     */
    public String refreshToken(String token) {
        try {
            Claims claims = getClaimsFromToken(token);
            Long expiration = claims.getExpiration().getTime();
            Long issuedTime = claims.getIssuedAt().getTime();

            Long now = System.currentTimeMillis();
            //中间时间
            Long midTime = (expiration - issuedTime) / 2 + issuedTime;
            if (now > midTime){
                claims.put(Claims.ISSUED_AT, new Date());
                return generateToken(claims);
            }

        } catch (Exception e) {

        }
        return token ;
    }

    /**
     * 验证令牌
     *
     * @param token       令牌
     * @param userDetails 用户
     * @return 是否有效
     */
    public Boolean validateToken(String token, UserDetails userDetails) {
        User user = (User) userDetails;
        String username = getUsernameFromToken(token);
        return (username.equals(user.getUsername()) && !isTokenExpired(token));
    }

    public static void main(String[] args) {
        String password = new BCryptPasswordEncoder().encode("haoclay");
        System.out.println("password = " + password);
    }
}